The present invention relates to digital data communications systems and specifically to a rate converting technique that permits a digital multiplexer to support any data rate that is less than half of its design rate.
The need for the present invention may arise in a limitless number of ways. For instance, a transmission facility or data port that is designed to carry traffic at a particular data rate may require an exchange with a system operating at another data rate. This task has been alleviated to some extent by the prior art techniques disclosed in the following patents:
U.S. Pat. No. 4,258,433 issued to Hershtal et al on 24 March 1981 and U.S. Pat. No. 2,979,565 issued to Zarcone on 11 April 1961.
The Hershtal patent discloses a digital data communication network having differing data transmission rate capabilities for interconnecting terminal devices when either the terminal devices operate at different data rates, or they are to be interconnected over data links in the network which normally operate at different data rates.
The Zarcone patent discloses a multiplexing synchronizer at the receiving end of a multiplex transmission line which employs the codes transmitted thereover to keep the receiving apparatus in condition to receive the codes both in proper order and in proper timing with each code.
While the prior art devices do allow the successful exchange of data between digital data devices operating at separate data rates, the prior art systems are constrained by data rates that are multiples of each other to avoid errors.
In view of the foregoing discussion, it is apparent that there currently exists the need for a rate converting technique that provides an interface capability between systems possessing data rates that are non-multiple of each other. The present invention is directed toward satisfying that need.